Relevant information for open solicitation of volunteers
for areas to explore the feasibility of constructing a final
repository for high-level radioactive waste ........... 3
Siting Factors
for the Selection of Preliminary
Investigation Areas
Nuclear Waste Management Organization of Japan (NUMO)
Site Planning and Public Relations Department
Mita NN Building 2F.
1-23, Shiba 4-chome, Minato-ku, Tokyo 108-0014
TEL: +81-3-4513-1116
FAX: +81-3-4513-1299
Website URL: http://www.numo.or.jp
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December 2002
C Nuclear Waste Management Organization of Japan
All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, electric or mechanical,
including photocopy, recording, or any information storage and retrieval system, without permission in writing from the publisher.
古紙配合率100％再生紙を使用しています
Nuclear Waste Management Organization of Japan
<1 > Introduction
Siting Factors for the Selection of
Preliminary Investigation Areas
List of Contents
In accordance with the “Specified Radioactive Waste Final Disposal Act”
(the Final Disposal Act), the Nuclear Waste Management Organization of Japan
<1>
Introduction ............................................................................................ 2
<2>
What are Preliminary Investigation Areas?
(NUMO) will openly solicit for “areas to explore the feasibility of constructing a
final repository for high-level radioactive waste” (volunteer areas), as part of the
procedure for selecting “Preliminary Investigation Areas” (PIAs).
................................................ 3
Literature surveys will be carried out for the volunteer areas and their
surroundings and PIAs will then be selected from these areas, based on the
<3>
Classification of Siting Factors
<4>
Selection Procedure for Preliminary Investigation Areas
................................................................ 5
results of the surveys.
In selecting PIAs, it is important to make clear the reasons for the selection.
and Application of Siting Factors
................ 7
Literature surveys will be implemented based on “Siting Factors for the Selection
of PIAs” (siting factors), which define the factors and principles applied in
<5>
selecting PIAs .
Content of Siting Factors
Evaluation Factors for Qualification (1) Earthquakes, Fault Activity
....... 9
...................... 13
Evaluation Factors for Qualification (2) Igneous Activity
In order to understand what siting factors are and how PIAs will be selected,
NUMO hopes that each municipality(city, town or village) will refer to this
material when considering applying as a volunteer area.
This material firstly provides an overall framework for the siting factors,
........................ 15
Evaluation Factors for Qualification (3) Uplift / Erosion
followed by detailed descriptions of each factor.
Evaluation Factors for Qualification (4)
Quaternary Unconsolidated Deposits
Evaluation Factors for Qualification (5) Mineral Resources
Favorable Factors
1
..... 17
................... 18
............................................................................... 19
........................... 20
Attachment Figure 1
Distribution of Active Faults in Inland Areas
Attachment Figure 2
Distribution of Active Faults in Offshore Areas
Attachment Figure
g
3
Distribution of Quaternary Volcanoes ...................................... 22
........................ 21
Direct inquiries about this document or the open solicitation procedure to
Site Selection Group, Site Planning and Public Relations Department
Nuclear Waste Management Organization of Japan
Mita NN Building 2F
1-23, Shiba 4-chome, Minato-ku, Tokyo, 108-0014
TEL: +81-3-4513-1116
FAX: +81-3-4513-1299
Website URL: http://www.numo.or.jp
2
<2 > What are Preliminary Investigation Areas?
A final repository site will be selected via a stepwise process as specified in
the Final Disposal Act:
Three Stages of the Selection Process
All Japan
Selection of Preliminary Investigation Areas (PIAs)
→ Selection of Detailed Investigation Areas (DIAs)
→ Selection of a Repository Site
The PIAs will be selected from volunteer areas and their surroundings, based
on the results of literature surveys carried out for these areas. DIAs will then be
selected from the PIAs and a repository site from the DIAs. Construction of the
repository will start following a safety review by the national government.
Where information that can be obtained by literature survey is limited, further
investigations will be conducted at later stages to allow an appropriate judgment to
be made based on sufficient information.
Preliminary investigations include borehole survey, geophysical prospecting,
etc. The results of the preliminary investigations provide input for determining
compliance with requirements such as stability of geological formations, no
obstruction to drift excavation, minimizing potential adverse impacts on
underground facilities due to groundwater flow, and so on. DIAs will be selected
from the PIAs that meet these requirements.
At the detailed investigation stage, measurements and tests in underground
investigation facilities, as well as detailed surface explorations, will be carried out.
Based on the results of these detailed investigations, the suitability of a site for
repository construction will be determined based on the physical and chemical
properties of the geological environment and, finally, a suitable repository site will
be selected from the DIAs.
In conducting each selection stage, NUMO’s assessment criteria will be
defined in accordance with national safety assessment guidelines that are being
developed simultaneously.
Each investigation in the selection process will provide the in-depth
information required for designing and constructing a repository, including
information on the geological environment required for assessing the suitability of
a potential repository site.
PIAs
DIAs
A Repository site
Explorations such as
borehole survey
Measurements and
tests in underground
investigation facilities
Construction of a repository
Selection of PIAs
Investigation areas:
Volunteer areas and their
surroundings
Investigation methods:
Literature surveys
Objectives:
To confirm that there is no
record of significant
movement in geological
formations due to
earthquakes, fault activity,
igneous activity, uplift, erosion
and other natural
phenomena, and to
verify the low likelihood
of significant movement in the
future due to natural
phenomena
(such as earthquakes
and so on).
Selection of DIAs
Investigation areas: PIAs
Investigation methods:
Borehole survey,
Geophysical prospecting, etc.
(preliminary investigations)
Objectives:
To confirm that the
geological formations for the
repository and their
surroundings are stable and
have no obstruction to
excavating drifts, small
potential adverse impacts on
underground facilities due to
groundwater flow and so on.
Selection of a repository
site
Investigation areas: DIAs
Investigation methods:
Detailed surface explorations,
measurements and tests in
underground investigation
facilities
(detailed investigations)
Objectives:
To confirm the suitability of
repository construction based on
the physical and chemical
properties of the geological
environment for the repository.
Laws and regulations besides the Final Disposal Act, such as regulations
covering protection and development of the natural environment, will also be
respected at the stages of repository site selection, construction and operation.
3
4
<3 > Classification of Siting Factors
What are siting factors?
The goal of selecting PIAs is to identify areas for conducting
preliminary investigations, excluding areas that would clearly be
unsuitable as a repository site, based on data and information
obtained through literature surveys.
The siting factors define the factors to be examined in the
assessment in selecting PIAs; the principles for the assessment are
defined taking into account the “Requirements of Geological
Environment to Select Preliminary Investigation Areas of HighLevel Radioactive Waste Disposal”, as well as the legal requirements
for PIAs prescribed in the Final Disposal Act and associated
regulations (legal requirements).
Siting factors consist of factors relating to legal requirements
(Evaluation Factors for Qualification; EFQ) and favorable factors for
additional assessment (Favorable Factors; FF).
Favorable Factors
Favorable Factors (FF) are not part of the legal requirements for PIAs, but have to be
considered by NUMO in their selection procedure. In accordance with NUMO’s policy of
promoting the disposal project while taking into account “economic and operational
efficiency premised on an assurance of safety”, these factors are defined as those that are
relevant during the literature surveys for DIA selection, repository site selection, repository
construction and operation.
For areas where compliance with legal requirements satisfies the EFQ, the
characteristics of PIAs will be assessed comprehensively in terms of FF. A comparative
assessment will also be carried out prior to PIA selection if necessary.
The assessment results based on FF will be used as input for investigation programs
and repository design studies.
Evaluation Factors for Qualification
PIAs must meet specified legal requirements. The Evaluation Factors for Qualification
(EFQ) are factors to assess compliance with legal requirements and to define specific
assessment criteria.
Siting Factors for Selection of PIAs
Legal requirements for PIAs are listed as follows:
Evaluation Factors for Qualification (EFQ)
a. There should be no record of significant movement in geological formations
due to earthquake or fault activity, igneous activity, uplift, erosion and other
natural phenomena;
b. The possibility of significant movement in the future due to earthquake or
fault activity, igneous activity, uplift, erosion and other natural phenomena
Factors used to assess compliance with legal requirements of PIAs
(earthquake and fault activity, igneous activity, uplift, erosion, unconsolidated
Quaternary deposits and mineral resources)
Nationwide Evaluation Factors (NEF)
should be small;
c. There should be no record of unconsolidated deposits that have been
deposited during the Quaternary period (i.e. in the last 1.7 million years);
Factors used to assess suitability of PIAs based on consistent nationwide criteria
Reference: Nationwide documents designated by NUMO
d. There should be no record of mineral resources that are economically
valuable.
Site-specific Evaluation Factors (SSEF)
Factors used to assess suitability of PIAs based on literature surveys for each
The EFQ include earthquake and fault activity, igneous activity, uplift, erosion,
unconsolidated Quaternary deposits and mineral resources. They are grouped into
volunteer area and its surroundings
Reference: Nationwide/regional documents and other informations for volunteer areas
Nationwide Evaluation Factors (NEF) and Site-specific Evaluation Factors (SSEF).
NEF are used to assess compliance of PIAs with legal requirements, based on
consistent criteria derived from nationwide information. Areas with potentially active
faults or volcanoes, and with a risk of significant movement in geological formations over
the next tens of thousands of years, will be excluded from the PIAs.
SSEF are used to assess compliance of PIAs with requirements, based on literature
Favorable Factors (FF)
Factors used to assess characteristics of PIAs comprehensively and comparatively if
necessary for areas where compliance with the legal requirements has been confirmed.
Reference: Nationwide/regional documents and other informations for volunteer areas
surveys for each volunteer area and its surroundings.
(1)"Requirements of Geological Environment to Select Preliminary Investigation Areas of High-Level Radioactive
Waste Disposal", Nuclear Safety Commission, September 30, 2002
5
6
<4> Selection Procedure for PIAs and Application of Siting Factors
Selection Procedure for Preliminary Investigation Areas and Siting Factors
Selection of PIAs
When selecting PIAs, NUMO will evaluate the results of literature surveys using siting
factors, define suitable areas for preliminary investigations and prepare a corresponding report.
PIAs will thus be selected according to a procedure prescribed in “Response after Receipt of
Application”, which is attached to the “Instructions for Application”. PIA selection requires the
approval of the Ministry of Economy, Trade and Industry (METI).
Municipalities
NUMO
Start open solicitation
Application of Siting Factors and Procedure
1. The start of the literature surveys will be notified to the volunteer areas ( i ).
NUMO will notify the start of literature surveys for volunteer areas that are acknowledged
as potential areas for survey in terms of the “Prior confirmation of the volunteered area’s
geological conditions” prescribed in the “Instructions for Application” (one of the reference
materials used for open solicitation of volunteer areas). The assessment principles for
Nationwide Evaluation Factors (NEF) for fault activity and igneous activity will be applied to
the “Prior confirmation of the volunteered area’s geological conditions” to identify conditions
to be avoided in a volunteer area. NUMO should be consulted if there are any questions
regarding volunteering.
2. NUMO will conduct literature surveys (ii).
a. NUMO will conduct literature surveys for volunteer areas and their surroundings. The
survey areas will be large, to allow a range of information to be obtained for applying the
siting factors.
b. Suitability as PIAs will be checked using NEF and Site-specific Evaluation Factors (SSEF).
Areas confirmed as being suitable will then be subject to a comprehensive assessment of
their characteristics using Favorable Factors (FF), and to a comparative assessment if
necessary.
c. Materials used in the literature surveys will be drawn from open information, the quality
and reliability of which will be checked by NUMO.
3. The area for a PIA is defined (iii).
The area for a PIA will be defined based on the results of literature surveys.
a. Regions identified as falling into areas with active faults or igneous activity, etc., as
prescribed in the Evaluation Factors for Qualification (EFQ), will be excluded from the
PIAs.
b. A PIA may be larger than a volunteer area, depending on location with respect to areas with
active faults and igneous activity and the size of the volunteer area. The zone outside the
actual volunteer area will be subject to preliminary investigations, but will not be eligible
for selection as a repository site.
4. The surroundings of PIAs may also be investigated (iv).
In order to evaluate PIAs, supplementary investigations may be carried out in surrounding
areas to check for active faults, igneous activity, uplift, erosion and so on. The investigations
carried out simultaneously with the preliminary investigations will include surveys of active
faults, volcanoes and geomorphic features, etc.
Volunteer area ( i )
Literature survey
area (ii)
Geomorphic surface
where uplift can be
quantified
(A case that is not
included in the PIA.)
PIA (iii)
(including
volunteer
Supplementary
investigation area (iv)
Active fault that falls
under the NEF
Image of defining PIAs.
7
Area within 15km radius
of the center of a Quaternary volcano that
falls under the NEF
Zone affected by thermal and hydrothermal
activity identified by
specific literature surveys
Active fault identified by
specific literature surveys
● Instructions
Send information
f m
package
Please feel free
to consult NUMO on
any question when
considering
volunteer.
Volunteer
for Volunteer
Concepts
● Siting Factors for Selection
of PIAs
● Approach for Outreach Scheme
● Repository
Check if a volunteer area is suitable for literature surveys based on the “Geological Conditions of Volunteer Areas”.
Notify thee start of literature surveys.
Implementation of literature surveys
Verify the suitability of PIA based on the
NEF and SSEF.
Characteristics of PIA will be assessed
comprehensively using FF and subject to
relative comparison if necessary.
Laws and regulations besides
the
h Final
Fi l Disposal Act will
be considered.
Define “PIAs”
Prepare a report on the selection of PIAs.
An application for the selection of PIAs will be submitted according to
the procedures prescribed in the “Response after Receipt of Application”
attached to the “Instruction for Application”, taking comments of local
residents into account.
Accordingly, PIAs will be determined with the approval of METI, considering comments by municipalities and prefectural governors concerned.
8
<5 > Content of Siting Factors
qu
E th
Earthquake,
k F
Fault
lt A
Activity
ti it
i
Evaluation Factors for Q
Qualification
ualification (1)
(1
( )
Major effects on a repository:
(A) “Fault activity” that may cause earthquakes and displacement/
deformation of geological formations;
Vibration on the
surface.
(B) Earthquake vibration;
(C) “Changes in the geological environment” before and after an
earthquake, such as generation of fractures and changes in flow and
chemical properties of groundwater.
Less vibration than
at the surface.
The impact of vibrations on surface facilities can be dealt with
using the same seismic (earthquake-resistant) design as for
conventional
nuclear
facilities.
Earthquake
vibrations
Seismic impact
on groundwater
flow is transient
and small.
deep
Vibration deep
underground is
very small.
underground are known to be smaller than at the surface and the
impact on underground facilities will thus be less than for surface
facilities.
Based on previous observations, changes in the geological
environment are expected to be small and their impact on the
Final disposal facility will be constructed where there is
no possibility of significant impacts due to fault activitiy.
repository will not be significant,.
Hence, (B) and (C) above will not be assessed in the selection of
PIAs; they will be further investigated subsequent to the preliminary
investigations, in order to examine their impact on a repository.
Events that cause “significant movement in geological
Seismic Impacts on the Geological Environment
Hypocenter
Several km - 20km underground
formations” will include (A) fault activity associated with
destruction/fracturing of rock that may have a significant impact on a
repository. “Active faults, folds and flexures” (active faults, etc.) are
identified by literature survey as being potentially active in the
future and their impact is thus considered to be significant and
problematic for designing the layout of the repository. Thus, siting
factors are defined as follows:
9
10
< 5 > Content of Siting Factors
Evaluation Factors for Qualification (1)
Earthquake, Fault Activity
Nationwide Evaluation Factors:
PIAs are defined as excluding locations with active faults identified by
nationwide literature, based on aerial photographs for inland areas and
sonic profiling for offshore
mountains and plains, active faults may cause bifurcation some time during the next tens of thousands of
years. Also, when an earthquake swarm is generated during extension of an active fault, the active fault
may extend further during the next tens of thousands of years. Hence, these effects will be investigated
thoroughly on an individual basis and zones with potential extensions will be excluded from PIAs.
With reference to “d”: Zones where clear large-scale active folds or flexures are distributed may
cause significant deformation of a repository during the next tens of thousands of years. Hence, these
Principles for assessment
Most faults that have shown repeated activity and significant displacement
have left topographic evidence in inland areas and in surface deposits in offshore areas. The identification
effects will be investigated thoroughly on an individual basis and zones with potential active folds and
flexures will be excluded from PIAs.
of active faults should, in principle, be based on detailed in situ investigations, but they will in fact be
identified based on a study of nationwide information.
Potentially significant impacts on a repository of active faults indicated in the literature below cannot
be ruled out given the relevant timescale of several tens of thousands of years or more. Therefore, PIAs
When the presence of active faults, etc. cannot be identified clearly by the literature surveys, any
presence of such features that may affect the construction of a repository will be further investigated
during the stage of preliminary investigations and subsequent investigations.
will exclude areas where such active faults are located.
Active faults for the purpose of selecting PIAs include active faults and inferred active faults
documented in the “1 : 2,000,000 Active Fault Map of Japan” (2002)(1), based on aerial photographs and
surface geological surveys for inland areas, and faults (normal, reverse, strike-slip and unclassified faults)
indicated in the “Quaternary Structural Map of Japanese Waters” (2001)(2), based on sonic profiles and
The content of siting factors with respect to fault activity relates to a repository for HLW that
requires long-term safety to be ensured for the next tens of thousands of years. The period for assessment
of local disaster prevention plans, miscellaneous plans and designs of nuclear facilities and general
structures will be different from the preceding case and hence the siting factors will not be applied.
boreholes for offshore areas. (Refer to attached Fig. 1 and 2)
Site-specific Evaluation Factors:
In terms of active faults that have shown repeated activity and significant
displacement, and other related natural phenomena, locations or zones that
clearly fall into the following categories will be excluded from PIAs:
a. Locations where active faults are identified by literature information other
than information used for the Nationwide Evaluation Factors
b. Extent in the fault crushed zone and surrounding deformation zones
c. Zones that are likely to have bifurcation of a fault
d. Zones with folds or flexures that have been active for the past hundreds of
thousands of years
Principles for assessment
With reference to “a”: Locations where active faults can be easily identified
by specific literature surveys, including information that falls under active faults in the Nationwide
Deformation zone
Fault crushed zone
Zone of fault
gouge
Zone of
fault breccia
a
Cataclasite
zone
Characteristics of components of the fault
crushed zone vary depending on the scale
and depth of generation of the crushed
zone.
Width of deformation band of active faults
Evaluation Factors, are excluded from PIAs.
With reference to “b”: Extent within the crushed zone of a fault that may cause fault activity may
also cause significant deformation of a repository. Hence, considering three-dimensional features of faults
Intact rock
Plain
Basin
Active
fault Bifurcation
II
Active
fault
I
Active fold range
Mountain
such as strike and dip, fault crushed zones that include fault gouge, fault breccia and cataclasite, etc., and
Active flexure range
their surrounding deformation zones, will be excluded from PIAs. Because the extent of fault crused
zones and deformation zones will vary depending on the characteristics of the fault and the surrounding
rocks, thorough investigations will be conducted on an individual basis.
With reference to “c”: In a case such as a reverse fault zone located near the boundary between
(1) T. Nakata, T. Imaizumi eds.(2002): “Digital active fault map of Japan”, attached Figure, 1 : 2,000,000 Active Fault
Map of Japan, University of Tokyo Press
(2) E. Tokuyama, E. Honza, M. Kimura, S. Kuramoto, J. Ashi, N. Okamura, H. Arato, Y. Ito, W. Soh, R. Hino, T.
Nohara, H. Abe, S. Sakai, and K. Mukaiyama (2001): “Tectonic development in the Regions around Japan since
the Latest Miocene”, attached Figure, Quaternary Structural Map of Japanese Waters, Journal of the Japan
Society for Marine Surveys and Technology vol. 13, No. 1
11
When there is a reverse fault near boundaries between mountain and plain,an active fault may cause
bifurcation (from I to II in the Figure) in several tens
of thousand of years in the future..
Bifurcation of an active fault
Range of active folds and flexures
12
< 5 > Content of Siting Factors
Evaluation Factors for Qualification (2)
( )
Igneous Activity
Activity
y
“Igneous activity”, including magmatic intrusion, volcanic
eruption and thermal and hydrothermal activity, may cause direct
damage to the repository. These are considered to fall under
“significant movement of geological formations” as prescribed by
law. Hence, siting factors are defined as follows:
Principles for assessment
Magmatic intrusion and volcanic eruptions caused by magma rising
from deep underground chambers have to be avoided, as these phenomena may cause significant
direct damage to a repository. For this reason, areas that may be subject to magmatic intrusion
or eruption over tens of thousands of years into the future will be excluded from PIAs.
Quaternary volcanoes in Japan are normally found in specific regions and this situation has
not changed significantly for the last two million years in general. Hence, it is reasonable to
expect that activity in the next tens of thousands of years will be limited to similar regions as at
present. It is known that older volcanoes have a larger magma activity area, the extent of which
is expected to be a maximum of 30km (a radius of around 15km from the center of a
volcano)(1), even considering a period of tens of thousands of years. In addition, based on data
in the Catalogue of Quaternary Volcanoes in Japan(2) (refer to attached Fig. 3), for almost all
volcanoes (except some special cases where volcanoes belong to monogenic volcano group with
a wide distribution, or have large calderas), the magmatic activity area is estimated to be within
a circle with a 15km radius from a representative location of the volcano.
Site-specific Evaluation Factors:
Outside a circle of 15km radius from the center of Quaternary volcanoes,
PIAs will also exclude areas that are definitely expected to have magmatic
intrusions or eruptions in the next tens of thousands of years. In addition,
areas that are expected to have significant thermal effects, highly acidic
thermal waters or significant hydrothermal convection will also be
excluded from PIAs.
In volcanoes, several conduits are generated by bifurcation
during magma rising to the surface through conduit from the
underground magma chamber. This area is called the
magma activity area, which can be roughly estimated from
the distribution of lateral volcanoes, lateral craters and dikes.
The extent of the circle in the nationwide evaluation factors
was established based on evidence that the magmatic
activity areas during several tens of thousand of years to
several hundreds of thousand of years were within about a
15 km radius.
Thermal or hydrothermal impacts due to geothermal activity
and hydrothermal convection could extend beyond this zone.
Principles for assessment
For areas outside a circle of 15km radius from the center of
Quaternary volcanoes, distributions of Quaternary volcanoes, craters and dikes will be
examined in detail on an individual basis and the possibility of magmatic intrusion or eruption
will be determined.
In addition, the generation of significant heat, highly acidic thermal waters and
hydrothermal convection have to be avoided because they may have a significant impact on a
repository.
Conceptual View of Igneous Activity and Surroundings of a Volcano
(Example of a Composite Volcano)
In case of the areas where the presense of Quatarnary volcanoes and significant impacts due
to igneous activity cannot be identified from literature surveys, investigations will be continued
into the preliminary investigation phase or subsequent investigation phases.
Nationwide Evaluation Factors:
Considering the extension of areas of magmatic activity during the next
tens of thousands of years, areas within a 15km radius of the center of
Quaternary volcanoes will be excluded from PIAs.
13
The content of siting factors for volcanoes described above applies to a repository for HLW
that requires to ensure long-term safety for the next tens of thousands of years. Assessment
periods for local disaster prevention plans, miscellaneous plans and designs of nuclear facilities
and general structures will be different and the above siting factors will not be applied.
(1) Eiji Nakata, Kazuhiro Tanaka (2001): Influence of magma intrusion on the bedrock-The distribution of volcanic
vent around the active volcano in Japan-: Abstract of 2001 annual meeting of Japan Society of Engineering
Geology
(2) Committee for Catalogue of Quaternary Volcanoes in Japan, eds. (1999): Catalogue of Quaternary Volcanoes in
Japan, v.1.0 (CD-ROM), Volcanological Society of Japan
14
< 5 > Content of Siting Factors
Evaluation Factors for Qualification (3)
( )
Uplift / Erosion
Erosion
Uplift is a phenomenon that raises wide areas of land. In regions
where uplift occurs, streams, rainfall, wind and glaciers will erode
the raised land surfaces. However, in regions with significant uplift
formed over a long period of time, erosion commensurate with uplift
may occur. If the erosion is significant, emplaced HLW (vitrified
waste) may eventually reach the surface.
Hence, considering that significant uplift and erosion represent
“significant movement of geological formations”, siting factors will
be defined as follows:
Terrace surface A
Terrace surface B
Terrace surface C
Terrace surface D
As a result of uplift at the coast, terrace surfaces have been
formed in order from A to D and geomorphic surfaces remain
even now. The topography also indicates that the uplifted
terrace surface has been eroded by a river.
Site-specific Evaluation Factors:
Areas where there is clear evidence of uplift amounting to more than 300m
during the last 100,000 years will be excluded from PIAs.
Principles for assessment
The trend of existing uplift and prediction of such movement in the
future can generally be identified from geomorphic surfaces of terraces. Many tiered
geomorphic surfaces have been formed during the past hundreds of thousands of years. In
particular, geomorphic surfaces formed approximately 125,000 years ago are well preserved all
over the country. From various evidence and results obtained from aerial photographs, the
amount of uplift during the past 100,000 years can be determined relatively accurately based on
the data for these geomorphic surfaces.
On the other hand, it is not so easy to identify the long-term effects of erosion. In general,
erosion amount associated with uplift is smaller than the amount of the uplift. However, when
uplift is significant, significant erosion may also be expected. Taking the most conservative
case, volumes of uplift and erosion are expected to be equal.
Based on geological evidence from the last hundreds of thousands of years, the total amount
of uplift during the past 100,000 years will be used as a measure for the assessment of uplift and
erosion.
The possibility of vitrified waste reaching the surface due to uplift and erosion can be
avoided by selecting an adequate disposal depth. The disposal depth is defined as 300 m or
greater by the Final Disposal Act. In the selection of PIAs, areas where uplift in the past
100,000 years has definitely exceeded 300 m will thus be excluded from PIAs.
Where the effects of uplift and erosion are not evident from literature surveys, they will be
investigated in detail at the preliminary investigation stage or in subsequent investigations.
In addition, the movement of vitrified waste towards the surface due to uplift and erosion
may cause changes in the flow patterns and chemical properties of groundwater and the
transport of radioactive substances contained in the vitrified waste. However, these effects are
difficult to determine based on literature surveys and they will therefore be examined at the
preliminary investigation stage or in subsequent investigations.
Uplift and erosion (marine terrace)
15
16
< 5 > Content of Siting Factors
Evaluation
E
l ti
Factors
F t
for
f Qualification
Q lifi ti
(5)
( )
Evaluation Factors for Qualification (4)
( )
Quaternary Unconsolidated
Unconsolidated Deposits
A
Mineral Resources
Geological formations where Quaternary unconsolidated deposits
are widely distributed have low strength, which may cause difficulties
in the construction of underground facilities. In addition, taking into
consideration potential difficulties in maintenance and management of
underground facilities during operation, siting factors will be defined as
follows:
Site-specific Evaluation Factors:
Site-specific Evaluation Factors:
PIAs will exclude areas where the geological formation intended for
repository construction is composed of Quaternary unconsolidated
deposits.
Principles for assessment
In order to prevent inadvertent human intrusion into the final
disposal facility through exploration or mining of mineral resources,
siting factors are defined as follows:
Unconsolidated gravels, sands and muds deposited in the Quaternary
period are termed Quaternary unconsolidated deposits. It is considered to be difficult to
Concerning the geological formation for final disposal, PIAs will exclude
areas with mineral resources that are economically valuable.
Principles for assessment
With a view to preventing human intrusion, areas with mineral
resources that are considered to be economically valuable will be excluded from PIAs.
construct and maintain underground facilities in geological formations with low-strength
Mineral resources are defined in the Mining Law. To determine the presence of
Quaternary unconsolidated deposits. If such deposits are present below a depth of 300m, and no
economically valuable resources, mining rights based on the Mining Law will be considered.
geological formation suitable for final disposal can be found, then such areas will be excluded
Mining rights are rights to mine on a large scale, which implies that minerals are definitely
from PIAs.
present that are, or could be, economically valuable. The establishment of mining rights for
mineral resources can be determined by checking written documents describing initiation or
If the presence of Quaternary unconsolidated deposits cannot be identified by literature
suspension of mining activities. Mineral resources currently being mined are considered to be
survey, their occurrence will be examined in the preliminary investigation stage or in
economically valuable. In addition, mineral resources under suspension (including those that
subsequent investigations.
have not yet been excavated) are considered to be economically valuable if their quality and
workable reserves are equal to, or better than, resources being actively mined. Hence, areas with
such mineral resources will be excluded from PIAs.
Mineral resources that have potential economic value, but do not fall into the preceding
category, will be examined in terms of their workability at the preliminary investigation stage or
in subsequent investigations.
300m or more
Resources that are not defined as “mineral resources” but have the potential to become
valuable, such as geothermal sources, hot springs, groundwater, etc., will be examined after the
selection of PIAs.
Minerals stipulated by the Mining Law
Geological formation for final disposal
A geological formation or rock mass
with sufficient extent, thickness and
properties to accommodate underground facilities.
It may consist of one or more geological formations or rock masses.
The minerals stipulated by the Mining Law include gold,
silver, copper, lead, bismuth, tin, antimony, mercury, zinc, iron, iron sulfide, chrome,
manganese, tungsten, molybdenum, arsenic, nickel, cobalt, uranium, thorium, phosphate,
graphite, coal, lignite, oil, asphalt, combustible natural gas, sulfur, gypsum, barite, alunite,
fluorite, asbestos, limestone, dolomite, silica stone, feldspar, pyrophyllite, talc, fireclay and
alluvial gold.
Geological formation for final disposal
17
18
Attachment Figure 1
Distribution of Active Faults in Inland Areas
< 5 > Content of Siting Factors
Favorable
a o a b e Factor
avorable
Factors
Fact
acto
Following the assessment based on the Evaluation Factors for
Qualification, the characteristics of PIAs will be assessed using
literature information on Favorable Factors (FF).
In this assessment, the PIAs will be evaluated based on the FF
considered as a whole rather than taken individually.
If necessary, a comparative assessment will be carried out to
select PIAs using FF.
Favorable Factors:
FF for evaluating the characteristics of PIAs are as follows:
a. Properties and conditions of geological formations:
Mechanical strength, conditions of deformation, fracturing, weathering and alteration,
geothermal gradient, configuration and scale of rock mass, uplift / erosion rate, potentially
unusual porewater pressures, swelling host rock, gas jets, rock-burst and large-scale water
inflow.
b. Hydraulic properties:
Groundwater flow rate and flow velocity, temperature, pH and Eh.
c. Investigation and assessment of the geological environment:
Scale, scope and duration of investigations, applicability of investigation technology and
assessment methods, ease of assessment and modeling of geological environments,
constraints on site investigation such as restrictions on land use.
d. Natural disasters during construction and operation:
Potential for critical natural disasters such as earthquakes, landslides and flooding.
e. Procurement of land:
Straightforward of procuring land.
f. Transportation:
Ease of transportation, such as distance from available harbors.
Principles for assessment
The factors mentioned above are assessed comprehensively.
The following characteristics are considered to be favorable:
a. Properties and conditions of geological formations
The geological formation for final disposal and overlying geological formations should have: rock with
sufficient strength, low deformation, fracturing, weathering and alteration, a low geothermal gradient,
sufficient extent of bedrock for accommodating underground facilities, slow uplift / erosion or areas
with continuous subsidence and a low likelihood of unusual porewater pressures, swelling host rock,
gas jets, rock-burst and large-scale water inflow.
b. Hydraulic properties
The geological formation for final disposal should have: a low groundwater flow rate and flow velocity,
low temperature and groundwater should not be extremely acidic or alkaline; geological formations and
groundwaters at the disposal site should not be extensively oxidized.
c. Investigation and assessment of the geological environment
The investigation scale, scope and cost should be reasonable and the duration of investigations should
not be excessively long; application of investigation technology and assessment methods should be
straightforward, as should assessment and modeling of geological phenomena such as igneous activity
and fault activity; constraints on site investigation, such as restrictions on land use, should be
manageable.
d. Natural disasters during construction and operation
There should be a low likelihood of critical natural disasters such as earthquakes, landslides and
flooding, from the viewpoint of safety during construction and operation.
e. Procurement of land
Procurement of land should be straightforward.
f. Transportation
Transportation should be easy, for example short distances between available harbors and the disposal
site.
出典：中田高・今泉俊文編
（２００２）
：「活断層詳細デジタルマップ」付図
図 ２００万の１日本列島活断層図、東京大学出版会
19
C University of Tokyo Press
Original scale of this map is one to two million.
All rights reserved. No part of this publication may b
be reproduced or
transmitted in any form or by any means, electric or m
mechanical,
including photocopy, recording, or any informatio
on storage and
retrieval system, without permission in writing from the publisher.
20
Attachment Figure 2
Distribution of Active Faults in Offshore Areas
出典：徳山英一ほか
（２００
１）
：
「日本周辺海域の中新世最末期以降の構造発達史」付図
日本周辺海域の第四紀地質構造図、海洋調査技術、第１
３巻第１号、海洋調査技術学会 海洋調査技術学会承認第１４００１号
21
C Journal of the Japan Society for Marine Surveys and Technology
Original scale of this map is one to two million.
All rights reserved. No part of this publication may be reproduced or
transmitted in any form or by any means, electric or mechanical,
including photocopy, recording, or any information storage and
retrieval system, without permission in writing from the publisher.
Attachment
添付図 ３ Figure 3
Distribution of Quaternary Volcanoes
出典：第四紀火山カタログ委員会編（１
９９９）
：
「日本の第四紀火山カタログ v.１.０
（CDーROM版）
」
付図
日本の第四紀火山、
日本火山学会
C Volcanological Society of Japan
Original scale of this map is one to three million.
All rights reserved. No part of this publication may be reproduced or
transmitted in any form or by any means, electric or mechanical,
including photocopy, recording, or any information storage
and retrieval system, without permission in writing from the
publisher.
22